Non-natural C-linked carbo-β-peptides with robust secondary structures

A C-linked β-peptide compound of the general formula I

• wherein n=0, 1, 2, 3 . . .
• R=H, Box, Cbz, Fmoc, acetyl or a salt formed with HCl or TFA;
• R1=—O alkyl, —O-aralkyl, -amine, alkylamine, or aryalkyl amine;
• R2=R3=R4=R5=H;
• or
• R2=sugar or hydroxy alkyl, amino alkyl, or amino thioalkyl, and R3=R4=R5=H;
• or
• R3=sugar or hydroxy alkyl, amino alkyl, or amino thioalkyl, and R2=R4=R5=H;
• or
• R4=sugar or hydroxy alkyl, amino alkyl, or amino thioalkyl, and R2=R3=R5=H;
• or
• R5=sugar or hydroxy alkyl, amino alkyl, or amino thioalkyl, and R2=R3=R4=H;
• or
• R2=R4=sugar or hydroxy alkyl, amino alkyl, or amino thioalkyl, and R3=R5=H;
• or
• R3=R5=sugar or hydroxy alkyl, amino alkyl, or amino thioalkyl, and R2=R4=H;
• or
• R2=R5=sugar or hydroxy alkyl, amino alkyl, or amino thioalkyl, and R3=R4=H;
• or
• R3=R4=sugar or hydroxy alkyl, amino alkyl, or amino thioalkyl, and R2=R5=H;
• or
• R2=R3=sugar or hydroxy alkyl, amino alkyl, or amino thioalkyl, and R4=R5=H;
• or
• R4=R5=sugar or hydroxy alkyl, amino alkyl, or amino thioalkyl, and R2=R3=H.